AD 98-21-07

This amendment adopts a new airworthiness directive (AD), applicable to certain British Aerospace Model Avro 146-RJ85A and RJ100A series airplanes, that requires a one-time inspection for evidence of machining (undercutting) into the web of the integral stringers of the bottom skin of the wings, and corrective actions, if necessary. This amendment is prompted by issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified by this AD are intended to prevent reduced wing strength and stiffness, and the onset of premature fatigue cracking, which could result in reduced structural integrity of the airplane.

Final rule

98-21-07 BRITISH AEROSPACE REGIONAL AIRCRAFT (Formerly British Aerospace Regional Aircraft Limited, Avro International Aerospace Division; British Aerospace, PLC; British Aerospace Commercial Aircraft Limited): Amendment 39-10815. Docket 98-NM-235-AD.
Applicability: Model Avro 146-RJ85A and RJ100A series airplanes, as listed in British Aerospace Service Bulletin SB.57-55, dated April 27, 1998, certificated in any category.

NOTE 1: This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (b) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.

Compliance: Required as indicated, unless accomplished previously.

To prevent reduced wing strength and stiffness, and the onset of premature fatigue cracking, which could result in reduced structural integrity of the airplane, accomplish the following:

(a) Within 6 months after the effective date of this AD, perform a one-time detailed visual inspection for evidence of machining (undercutting) into the web of the integral stringers of the bottom skin of the wings, in accordance with British Aerospace Service Bulletin SB.57-55, dated April 27, 1998.

(1) If no machining into the web is detected, no further action is required by this AD.

(2) If any machining into the web is detected, prior to further flight, measure the thickness of the web of the integral stringer in accordance with the service bulletin.

(i) If the web thickness is 0.099 inch or more, no further action is required by this AD.

(ii) If the web thickness is less than 0.099 inch, prior to further flight, repair in accordance with a method approved by either the Manager, International Branch, ANM-116, FAA, Transport Directorate, or the Civil Aviation Authority (or its delegated agent).

(b) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, International Branch, ANM-116. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, International Branch, ANM-116.

NOTE 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the International Branch, ANM-116.

(c) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished.

(d) Except as provided by paragraph (a)(2)(ii) of this AD, the actions shall be done in accordance with British Aerospace Service Bulletin SB.57-55, dated April 27, 1998, which contains the following list of effective pages:

Page Number
Revision Level
Shown on Page
Date
Shown on Page
1-4
Original
April 27, 1998
5-6
X
Not Dated

This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from AI(R) American Support, Inc., 13850 Mclearen Road, Herndon, Virginia 20171. Copies maybe inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

(e) This amendment becomes effective on November 10, 1998.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to certain British Aerospace Model Avro 146-RJ85A and RJ100A series airplanes was published in the Federal Register on August 13, 1998 (63 FR 43351). That action proposed to require a one-time inspection for evidence of machining (undercutting) into the web of the integral stringers of the bottom skin of the wings, and corrective actions, if necessary.

Comments
Interested persons have been afforded an opportunity to participate in the making of this amendment. No comments were submitted in response to the proposal or the FAA's determination of the cost to the public.

Conclusion
The FAA has determined that air safety and the public interest require the adoption of the rule as proposed.

Cost Impact
The FAA estimates that 5 airplanes of U.S. registry will be affected by this AD, that it will take approximately 16 work hours per airplane to accomplish the required inspection, and that the average labor rate is $60 per work hour. Based on these figures, the cost impact of the AD on U.S. operators is estimated to be $4,800, or $960 per airplane.
The cost impact figure discussed above is based on assumptions that no operator has yet accomplished any of the requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted.

Regulatory Impact
The regulations adopted herein will not have substantial direct effects on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government. Therefore, in accordance with Executive Order 12612, it is determined that this final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.

For the reasons discussed above, I certify that this action (1) is not a "significant regulatory action" under Executive Order 12866; (2) is not a "significant rule" under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act. A final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it may be obtained from the Rules Docket at the location provided under the caption "ADDRESSES."

List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety

Adoption of the Amendment
Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows:

PART 39 - AIRWORTHINESS DIRECTIVES
1. The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701.

39.13 [Amended]
2. Section 39.13 is amended by adding the following new airworthiness directive: